Extreme rainfall events are primary natural hazards, which cause a severe threat to people and their properties in populated cities, which are normally located in coastal areas in Vietnam. Analysing these events by us...Extreme rainfall events are primary natural hazards, which cause a severe threat to people and their properties in populated cities, which are normally located in coastal areas in Vietnam. Analysing these events by using a data series observed over years will support us to draw a picture of how the climate change impact on local environments. The purpose of this report is to understand the characteristics of the extreme rainfall events in MEKONG river delta （south VietNam）. Daily rainfall data in the period of 30 years for a meteorological station in each area were collected from the Vietnam National Hydro-meteorological Service. The extreme rainfall events were defined as those exceeding the 95th percentile for each station. The analytical results show that the rainfall values （95th percentile） are 37.4 mm/day at Nam Can station, 27 mm/day at My Thanh station, 22.4 mm/day at Hoa Binh station, 23.8 mm/day at Binh Dai station and 22.7 mm/day at Ben Trai station. The highest rainfall data ever recorded are 246.4 mm/day （Nam Can）, 174.5 mm/day （My Thanh）, 179 mm/day （Hoa Bin_h）, 187.3 mm/day （Binh Dai） and 136.3 mm/day （Ben Trai） during 1983-2012. The result of the Mann-Kendall tests show that there was a significant creasing of the rainfall at Nam Can, My Thanh station in two periods （1983-2012, 1998-2012） while no clear trend of the rainfall was recoreded at Hoa Birth, Binh Dai, Ben Trai station. In order to estimate the return period of the extreme rainfall events, the method General Extreme Value Distribution was used to calculate frequent distribution. The magnitudes of daily maximum rainfall were from 2 to 100 years. The results of return period show that maximum rainfalls are 46.6 mm at Nam Can station （highest） and 31.4 mm at Hoa Birth station （lowest） during 50 years. Similarly, maximum rainfalls are expected to be about 55.1 mm at Nam Can station and 37.2 mm at Hoa Birth station for 100 years.展开更多
Groundwater resources have considerable influences on the human population and socioeconomic development of Vietnam and the Mekong River Delta(MRD). This paper presents an overview of the relationship between climate ...Groundwater resources have considerable influences on the human population and socioeconomic development of Vietnam and the Mekong River Delta(MRD). This paper presents an overview of the relationship between climate change and groundwater in the MRD, including the challenges, strategies and technical measures. Our results showed that groundwater levels are related to other climate and hydrological variables(i.e., rainfall, river levels, etc.); therefore, the impacts of climate change on the groundwater resources of the Mekong delta are significant, especially on groundwater recharge. Based on the results of this study, it is recommended that groundwater development in the future should focus on reducing groundwater harvesting, enhancing groundwater quantity by establishing artificial works and exploiting surface water. This study suggests that the Artificial Neural Network(ANN) model is an effective tool for forecasting groundwater levels in periods of 1 month and 3 months for aquifers in the natural and tidal regime areas of the delta.展开更多
Vietnam is the land of all original and absorbed goddesses in Southeast Asia. Local goddesses such as Lieu Hanh, Ba Chua Kho, Thien Yana Ponagar, Ba Den, Ba Chua Xu or external goddess such as Xi Wangmu （西王母）, Kw...Vietnam is the land of all original and absorbed goddesses in Southeast Asia. Local goddesses such as Lieu Hanh, Ba Chua Kho, Thien Yana Ponagar, Ba Den, Ba Chua Xu or external goddess such as Xi Wangmu （西王母）, Kwan Yin （观音）, Yao Chi Jin Mu （瑶池金母）, Tian Hou （天後）, Mother Dragon Goddess （龙母娘娘）, Jin Hua Goddess （金花夫人） etc. all are worshipped simultaneously throughout the nation. Among those, the cult of Tian Hou has become the most typical external goddess belief which absorbs both the cults of Kwan Yin and Xi Wang Mu, at the certain extend, become a symbol of harmonization. The cult of Tian Hou originated in Fujian, China and was gradually brought into South Vietnam after the footsteps of South Chinese immigrants during 17th-20th century. There are around 50 Tian Hou temples built and owned by the ethnic Hoa （华族/Chinese） and the Vietnamese at the Mekong River Delta. In the Mekong residents＇ mind, Tian Hou is seen as a maritime goddess, a protector, a benevolent Mother Goddess who has been accepted through the channels of Mahayana Buddhism and traditional goddess beliefs in the local communities. This paper is to investigate the current situation of the cult of Tian Hou in the Mekong River Delta to highlight the basic characteristics of this cult in the region.展开更多
The destruction of the South Vietnamese rice (<em>Oryza sativa L</em>) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret;however, it rec...The destruction of the South Vietnamese rice (<em>Oryza sativa L</em>) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret;however, it received little media attention in the United States. Republic of Vietnam and United States (U.S.) militaries began destroying food crops (rice) in November of 1962 primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on 100,000 ha of mangrove forests and about 300,000 ha of rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Six Rainbow herbicides, commonly called Agent Orange, Agent Green, Agent Pink, Agent Purple, Agent White, and Agent Blue, were sprayed on wetlands, rice paddies, forests, mangroves, bamboo and military base perimeter fences to defoliate jungle vegetation, reveal guerilla hiding places and destroy the food supply of enemy troops. South Vietnamese farmers, U.S. and Republic of Vietnam military personnel, and communist insurgents were exposed to these herbicides with immediate and longer term impacts on personal health, civilian household food security and population-wide famine. Agent Blue (cacodylic acid, C<sub>2</sub>H<sub>2</sub>AsO<sub>2</sub>,) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the U.S. at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas including the Mekong Delta. Today arsenic contaminated rice and groundwater are growing concerns as neither naturally occurring arsenic nor anthropic arsenic have a half-life and cannot be destroyed. Anthropic arsenic has remained in the Mekong Delta environment for the last 60 years and added to persistent As contamination in water supplies, sediments and soils. Water soluble arsenic primarily leaches into the soil root zone and the groundwater or is carried by floodwater into adjacent waterways or volatilized under anaerobic rice paddy conditions as gaseous arsine. The health of 15 million Vietnamese people living in the Mekong Delta is at risk from the combination of manufactured and natural As in drinking water and food supply. The As in the contaminated rice paddy soil, sediment and water is up taken by fish, shrimp or by crop vegetation and trace amounts can end up in the food supply (rice grain) or be bioaccumulated by the fish, shrimp and birds which when eaten were bioaccumulated in the Vietnamese people. It is urgent that elevated As concentrations in water supplies and agricultural products be identified and mitigated through better run-off control and groundwater management;improved rice genetics and alternate crop selections;shifts in crop management associated with tillage, fertilization and phosphorus use;and systematic monitoring of food and drinking water.展开更多
文摘Extreme rainfall events are primary natural hazards, which cause a severe threat to people and their properties in populated cities, which are normally located in coastal areas in Vietnam. Analysing these events by using a data series observed over years will support us to draw a picture of how the climate change impact on local environments. The purpose of this report is to understand the characteristics of the extreme rainfall events in MEKONG river delta （south VietNam）. Daily rainfall data in the period of 30 years for a meteorological station in each area were collected from the Vietnam National Hydro-meteorological Service. The extreme rainfall events were defined as those exceeding the 95th percentile for each station. The analytical results show that the rainfall values （95th percentile） are 37.4 mm/day at Nam Can station, 27 mm/day at My Thanh station, 22.4 mm/day at Hoa Binh station, 23.8 mm/day at Binh Dai station and 22.7 mm/day at Ben Trai station. The highest rainfall data ever recorded are 246.4 mm/day （Nam Can）, 174.5 mm/day （My Thanh）, 179 mm/day （Hoa Bin_h）, 187.3 mm/day （Binh Dai） and 136.3 mm/day （Ben Trai） during 1983-2012. The result of the Mann-Kendall tests show that there was a significant creasing of the rainfall at Nam Can, My Thanh station in two periods （1983-2012, 1998-2012） while no clear trend of the rainfall was recoreded at Hoa Birth, Binh Dai, Ben Trai station. In order to estimate the return period of the extreme rainfall events, the method General Extreme Value Distribution was used to calculate frequent distribution. The magnitudes of daily maximum rainfall were from 2 to 100 years. The results of return period show that maximum rainfalls are 46.6 mm at Nam Can station （highest） and 31.4 mm at Hoa Birth station （lowest） during 50 years. Similarly, maximum rainfalls are expected to be about 55.1 mm at Nam Can station and 37.2 mm at Hoa Birth station for 100 years.
文摘Groundwater resources have considerable influences on the human population and socioeconomic development of Vietnam and the Mekong River Delta(MRD). This paper presents an overview of the relationship between climate change and groundwater in the MRD, including the challenges, strategies and technical measures. Our results showed that groundwater levels are related to other climate and hydrological variables(i.e., rainfall, river levels, etc.); therefore, the impacts of climate change on the groundwater resources of the Mekong delta are significant, especially on groundwater recharge. Based on the results of this study, it is recommended that groundwater development in the future should focus on reducing groundwater harvesting, enhancing groundwater quantity by establishing artificial works and exploiting surface water. This study suggests that the Artificial Neural Network(ANN) model is an effective tool for forecasting groundwater levels in periods of 1 month and 3 months for aquifers in the natural and tidal regime areas of the delta.
文摘Vietnam is the land of all original and absorbed goddesses in Southeast Asia. Local goddesses such as Lieu Hanh, Ba Chua Kho, Thien Yana Ponagar, Ba Den, Ba Chua Xu or external goddess such as Xi Wangmu （西王母）, Kwan Yin （观音）, Yao Chi Jin Mu （瑶池金母）, Tian Hou （天後）, Mother Dragon Goddess （龙母娘娘）, Jin Hua Goddess （金花夫人） etc. all are worshipped simultaneously throughout the nation. Among those, the cult of Tian Hou has become the most typical external goddess belief which absorbs both the cults of Kwan Yin and Xi Wang Mu, at the certain extend, become a symbol of harmonization. The cult of Tian Hou originated in Fujian, China and was gradually brought into South Vietnam after the footsteps of South Chinese immigrants during 17th-20th century. There are around 50 Tian Hou temples built and owned by the ethnic Hoa （华族/Chinese） and the Vietnamese at the Mekong River Delta. In the Mekong residents＇ mind, Tian Hou is seen as a maritime goddess, a protector, a benevolent Mother Goddess who has been accepted through the channels of Mahayana Buddhism and traditional goddess beliefs in the local communities. This paper is to investigate the current situation of the cult of Tian Hou in the Mekong River Delta to highlight the basic characteristics of this cult in the region.
文摘The destruction of the South Vietnamese rice (<em>Oryza sativa L</em>) crop using an arsenic-based herbicide known as Agent Blue during the American Vietnam War (1965-1972) was not a secret;however, it received little media attention in the United States. Republic of Vietnam and United States (U.S.) militaries began destroying food crops (rice) in November of 1962 primarily via aerial applications in the Mekong Delta and Central Highlands of South Vietnam. Spraying of Agent Blue on 100,000 ha of mangrove forests and about 300,000 ha of rice paddies just before rice harvest time resulted in the destruction of the standing crop and rendered the land contaminated with arsenic (As). Six Rainbow herbicides, commonly called Agent Orange, Agent Green, Agent Pink, Agent Purple, Agent White, and Agent Blue, were sprayed on wetlands, rice paddies, forests, mangroves, bamboo and military base perimeter fences to defoliate jungle vegetation, reveal guerilla hiding places and destroy the food supply of enemy troops. South Vietnamese farmers, U.S. and Republic of Vietnam military personnel, and communist insurgents were exposed to these herbicides with immediate and longer term impacts on personal health, civilian household food security and population-wide famine. Agent Blue (cacodylic acid, C<sub>2</sub>H<sub>2</sub>AsO<sub>2</sub>,) was the most effective of all the Rainbow herbicides in killing rice and grasses. Manufacturing of cacodylic acid began in the late 1950s in the U.S. at the Ansul Company chemical plant in Marinette, Wisconsin and Menominee, Michigan. During the Vietnam War, ocean going ships were loaded with 208-liter Agent Blue barrels and shipped via the St. Lawrence Seaway to the coast of South Vietnam. Arsenic (As) is a naturally occurring element that is found throughout SE Asia deltas including the Mekong Delta. Today arsenic contaminated rice and groundwater are growing concerns as neither naturally occurring arsenic nor anthropic arsenic have a half-life and cannot be destroyed. Anthropic arsenic has remained in the Mekong Delta environment for the last 60 years and added to persistent As contamination in water supplies, sediments and soils. Water soluble arsenic primarily leaches into the soil root zone and the groundwater or is carried by floodwater into adjacent waterways or volatilized under anaerobic rice paddy conditions as gaseous arsine. The health of 15 million Vietnamese people living in the Mekong Delta is at risk from the combination of manufactured and natural As in drinking water and food supply. The As in the contaminated rice paddy soil, sediment and water is up taken by fish, shrimp or by crop vegetation and trace amounts can end up in the food supply (rice grain) or be bioaccumulated by the fish, shrimp and birds which when eaten were bioaccumulated in the Vietnamese people. It is urgent that elevated As concentrations in water supplies and agricultural products be identified and mitigated through better run-off control and groundwater management;improved rice genetics and alternate crop selections;shifts in crop management associated with tillage, fertilization and phosphorus use;and systematic monitoring of food and drinking water.
